The U.S. Forest Service has tried to convince the public that prescribed burns and managed wildfires are good ways to maintain forest health, but the unfiltered wood smoke from both procedures is deadly, particularly for fetuses, infants, children and elders, says PrescribedBurns.com.

For vulnerable populations, such as people with asthma, chronic respiratory diseases, high blood pressure and cardiovascular diseases, short exposure to wood smoke can be fatal, the website says.

Wood smoke is 12 times more carcinogenic than cigarette smoke and kills at least 40,000 adults and children each year in the United States. Such smoke contains a toxic brew of more than 4,000 chemicals in gases and particulate materials that penetrate deep into the lungs. Sixty-nine of them are known human carcinogens, including arsenic, particulate matter, ozone, sulfur dioxide, carbon monoxide, hydrocarbons and dioxin.

In 2008 the American Lung Association published a warning about the dangers of burning wood.

“Burning wood emits harmful toxins and fine particles in the air that can worsen breathing problems and lead to heart and lung disease and early death,” it says.

Mechanical methods of dealing with unwanted trees, such as using tree thinning and mulching machines, remove only unwanted trees and brush, leaving healthful mulch instead of the charred remains of a forest.

Forest-protection advocates argue that leaving forests to nature and not “managing” them at all is preferable to human intervention.

After the Twin Cities regulated the large smokestack industries, our air quality initially improved. But officials have neglected the smaller fires ("More pollution clogs metro," April 25).

As back-yard recreational fires and wood-grill restaurants become increasingly popular, they add heavily to the burden of particulate matter that clogs the air in the Twin Cities. It would be far easier and less costly to eliminate this unnecessary wood smoke than to remove old cars from the road.

• The Surgeon General has determined that there is no safe level of exposure to ambient smoke!

• If you smell even a subtle odor of smoke, you are being exposed to poisonous and carcinogenic chemical compounds!

• Even a brief exposure to smoke raises blood pressure, (no matter what your state of health) and can cause blood clotting, stroke, or heart attack in vulnerable people. Even children experience elevated blood pressure when exposed to smoke!

• Since smoke drastically weakens the lungs' immune system, avoiding smoke is one of the best ways to prevent colds, flu, bronchitis, or risk of an even more serious respiratory illness, such as pneumonia or tuberculosis! Does your child have the flu? Chances are they have been exposed to ambient smoke!